The present invention relates to a flat sewing device without thread bobbins, and especially to a flat sewing device used in a sewing machine.
Referring to FIG. 1, the shuttle flat sewing device in the prior art is illustrated. The shuttle flat dewing device is installed on a sewing machine 50. The shuttle receiving groove 503 is installed below the sewing portion 501 of the sewing machine 50. A driving spindle 502a is installed at the center of the shuttle receiving groove 503. The driving spindle 502a is connected to a shuttle casing 502b. The shuttle casing 502b is extended with a shuttle receiving cavity 503. The shuttle casing 502b can be disposed in the shuttle receiving seat 502. The center of the shuttle receiving cavity 503 is installed with an axial rod 504. The edge of the axial rod 504 is installed with an annular groove 504a. The edge of the shuttle receiving cavity 503 is installed with a positioning notch 505. A lateral side of the sewing portion 501 of the sewing machine 50 is installed with a notch 506. Two sides of the notch 506 each are installed with a sliding track 507. A cover 508 can slide in the sliding track 507. A hollow shaft 61 extends from the interior of the shuttle 60. The outer lateral side thereof is installed with a movable elastomer 62 and a positioning rod 63. A press 64 extends from an outer edge of the shuttle 60. A thread bobbin 70 is further installed within the shuttle 60. A sewing thread 71 is wound around the interior of the thread bobbin 70.
Referring to FIGS. 1 and 2, as the sewing machine 50 is to be assembled, at first, the sewing thread 71 is wound around the thread bobbin 70. At the press 64, at the outer edge of the shuttle 60, the sewing thread protrudes out from the thread bobbin 70. The thread bobbin 70 is placed within the shuttle so that the central hole of the thread bobbin 70 is movably installed on the hollow shaft 61 in the shuttle 60. Then, the positioning rod 63 at the outer surface of the shuttle 760 is aligned with the notch 505 at an upper edge of the shuttle receiving cavity 503 in the shuttle receiving seat 502. Next, the shuttle 60 is installed in the shuttle receiving cavity 503 of the sewing machine 50 so that the hollow shaft 61 within the shuttle 60 is successfully installed in the shuttle receiving cavity 503 of the sewing machine 50. Then, the shuttle 60 is connected to an axial rod 504 at a center of the shuttle receiving cavity 503. The shuttle casing 502b is then connected to the driving spindle 502a at the center of the shuttle receiving seat 502. Finally, the cover 508 slides into the sliding tracks 507 at two sides of the notch 506 of the sewing machine 50.
However, since the length of the sewing thread 71 in the thread bobbin 70 is finite, the sewing length of the sewing thread 71 is equally finite. The sewing thread 70 must be replenished frequently for supplementing the sewing thread 71 in the thread bobbin 70. After the sewing thread 71 in the thread bobbin 70 is used up, in the sewing machine 50, the sewing thread 71 cannot be replenished immediately. The main thread of the sewing machine 50 will catch and break, and thus the thread must be rearranged at once. As a result, the efficiency of the sewing machine 50 is affected.
Moreover, since them material of the thread bobbin 70 is usually iron, and the sewing speed of the sewing machine 50 is very quick, the thread bobbin 70 is easily heated to a high temperature. When replenishing or supplementing the sewing thread 71 in the thread bobbin 70, the user must touch the thread bobbin 70 and may thereby be burned.
Moreover, since the thread bobbin 70 is easily heated to a high temperature, the worker generally wears gloves, but working under that condition is inconvenient.
Accordingly, the primary object of the present invention is to provide a flat sewing device without thread bobbins which is used with a large sewing thread supply, so as to increase the sewing length of the sewing machine. The sewing thread in a large spool need not be replenished frequently. The main thread of the sewing machine will not break frequently. Harm from burns is avoided since the worker does not have to touch a hot thread bobbin. Another object of the present invention is to provide a flat sewing device without thread bobbins.
To achieve these objects, the present invention provides a flat sewing device without thread bobbins. Therefore, it is unnecessary for a worker to touch a hot thread bobbin. The convenience of working with the present invention is an improvement as a worker need not wear a glove.
In order to achieve the aforesaid objects, the present invention provides a flat sewing device without thread bobbins comprising: a dynamic seat having screw holes at a front face thereof, and a driving spindle being installed at a lower edge near a center thereof; an oblong case having two inner sides each extending with a flange and being fixed to a front face of the dynamic seat by screws; an auxiliary seat, gears, spindle, rotary bearings, a hollow spindle, a hollow driving spindle, which are properly connected; and a shuttle casing extending with a receiving cavity. The thread is not frequently broken. The work of changing color can be accomplished successfully. It is unnecessary to detach the shuttle or other elements. The problems of replenishing and supplementing the sewing thread are removed by the present invention, it is unnecessary to frequently replenish the sewing thread. Thus, the performance of the sewing machine is improved.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawings.